Ammonium hydroxide (NH3[aq]), also
known as ammonia water, ammonical
liquor, ammonia liquor, aqua
ammonia, or aqueous ammonia, is a
solution of ammonia in
water. Although its name suggests a salt of the formula
NH4OH, it is not actually possible to generate samples
of NH4OH - it exists only in dilute aqueous
solutions.[3]

Saturated
Solutions

Like other gases, ammonia exhibits decreasing solubility in
solvent liquids as the temperature of the solvent increases.
"Ammonium hydroxide" solutions decrease in density as the
concentration of dissolved ammonia increases. At 15.5556 °C, the
density of a saturated solution is 0.88 g/mL and contain 35%
ammonia by mass, 308g/L w/v, (308 grams of ammonia per litre of
solution) and have a molarity of approximately 18 mole/L. At
higher temperatures, the molarity of the saturated solution
decreases and the density increases.

When solutions that are saturated at cold temperatures are
sealed in containers and subsequently warmed, the concentration of
the solution decreases and the vapor pressure of ammonia gas
increases. Unsealing such containers can lead to a burst of ammonia
gas. In extreme cases, the containers could rupture.

From a laboratory perspective, one should be aware that the
concentration of a saturated solution is continually dropping as
the container is handled in a warmer environment. Thus, old samples
of ammonium hydroxide will deviate from 18 M, as can be verified by
titration.

Applications

Household ammonia is dilute ammonium hydroxide, which is also an
ingredient of numerous other cleaning agents.

Prepare paintwork for newly painting an already painted surface
by cleaning the painted surface with household ammonia or ammonium
hydroxide.

Ammonium hydroxide is used in the meat packing industry. Some
companies add ammonium hydroxide to their beef.[5]

Laboratory
use

Aqueous ammonia is used in traditional qualitative inorganic
analysis as a complexant and base. Like many amines, it gives a
deep blue coloration with copper(II) solutions. Ammonia solution
can dissolve silver residues, such as that formed from Tollens'
reagent.

When ammonium hydroxide is mixed with dilute hydrogen
peroxide in the presence of a metal ion, such as
Cu2+, the peroxide will undergo rapid decomposition.

Ammonium hydroxide, also known as ammonia water, ammonical liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or simply ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although its name suggests a salt with composition [NH4+][OH−], it is not actually possible to isolate samples of NH4OH — it exists only in dilute aqueous solutions.[3]

Saturated solutions

Like other gases, ammonia exhibits decreasing solubility in solvent liquids as the temperature of the solvent increases. "Ammonium hydroxide" solutions decrease in density as the concentration of dissolved ammonia increases. At Template:Convert/°C, the density of a saturated solution is 0.88 g/ml and contains 35% ammonia by mass, 308 g/l w/v, (308 grams of ammonia per litre of solution) and has a molarity of approximately 18 mol L−1. At higher temperatures, the molarity of the saturated solution decreases and the density increases.

When solutions that are saturated at cold temperatures are sealed in containers and subsequently warmed, the concentration of the solution decreases and the vapor pressure of ammonia gas increases. Unsealing such containers can lead to a burst of ammonia gas. In extreme cases, the containers could rupture.

From a laboratory perspective, one should be aware that the concentration of a saturated solution is continually dropping as the container is handled in a warmer environment. Thus, old samples of ammonium hydroxide will deviate from 18 M, as can be verified by titration.

Applications

Household ammonia is dilute ammonium hydroxide, which is also an ingredient of numerous other cleaning agents, including many window cleaning formulas. In addition to use as an ingredient in cleansers with other cleansing ingredients, ammonium hydroxide in water is also sold as a cleaning agent by itself, usually labelled as simply "ammonia". It may be sold plain, lemon-scented (and typically colored yellow), or pine-scented (green).

In furniture-making, ammonium hydroxide was traditionally used to darken or stain wood containing tannic acid. Tannic acid with ammonium hydroxide or iron salts creates a brown stain which can be applied to wood. [5]

Ammonium hydroxide is used in the meat packing industry. Some companies treat their beef "with a pH enhancement process that forms ammonium hydroxide in the finished product."

Laboratory use

Aqueous ammonia is used in traditional qualitative inorganic analysis as a complexant and base. Like many amines, it gives a deep blue coloration with copper(II) solutions. Ammonia solution can dissolve silver residues, such as that formed from Tollens' reagent.

When ammonium hydroxide is mixed with dilute hydrogen peroxide in the presence of a metal ion, such as Cu2+, the peroxide will undergo rapid decomposition.